Bifit Insole Board Stiffness Transition for Footwear Weight Stability
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Solution Overview
Problem
Conventional hiking or work boots are heavy, leading to fatigue in the legs due to the weight they impose with each step, and existing lightweight designs may compromise stability and support.
Innovation Solution
A footwear assembly with a sole assembly featuring a U-shaped first insole board and a full-length bifit insole board, along with a transition member that provides stability in the heel and arch areas while increasing compliance in the forefoot area, allowing for a transition from flat foot to heel off and toe off phases of the gait cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional hiking or work boots are designed to provide stability and support, then the footwear becomes heavy, but if the weight is reduced, then stability and support are compromised
Solution Approach 1:
The insole board incorporates regions of different stiffness values, with a first region having a higher stiffness value than a second region. This local differentiation allows specific areas to provide enhanced stability and support where needed, while other areas remain more flexible and lightweight, thereby resolving the contradiction between overall weight reduction and localized stability requirements
Solution Approach 2:
The insole board is constructed as a composite structure with multiple regions having different stiffness characteristics. This composite approach enables the integration of both stiff and flexible properties within a single component, allowing the footwear to achieve both weight reduction and stability maintenance through material and structural composition
2Stability of the object's composition
If the insole board is made uniformly stiff to provide support, then stability is improved, but comfort and energy transfer during gait cycle are reduced
Solution Approach 1:
Different regions of the insole board are assigned different stiffness values matched to their specific functional requirements during the gait cycle. The higher stiffness first region provides stability during heel strike and flat foot phases, while the lower stiffness second region allows necessary flexion during heel off and toe off phases, thereby improving both stability and comfort
Solution Approach 2:
The insole board's stiffness characteristics are optimized to dynamically respond to different phases of the gait cycle. By having variable stiffness regions rather than a uniform structure, the footbed can adapt its mechanical properties throughout the walking motion, providing stability when needed and compliance when needed for natural foot movement
Data Source
AI summary
A footwear assembly with an insole assembly having a heel insole board above a midsole and a bifit insole board, which has a heel portion that is stiffer than a forefoot portion. The bottom edge flanges of the upper wrap around the sides of the bifit insole board's heel portion and arch portion rearward of an attachment transition area. At least a portion of the flanges are adhered between the bifit insole board and the heel insole board. The upper's flanges are positioned adjacent to sides of the bifit insole board's forefoot portion and arch portion forward of the attachment transition area without wrapping under the bifit insole board. The upper's flanges are stitched to a top or edge of the bifit insole board's forefoot portion and arch portion forward of the attachment transition area.